One example of conventional pumping-out apparatuses will be explained in reference to FIGS. 5(a), 5(b), and 5(c). As shown in FIG. 5(c), a pumping-out apparatus 1 can suction a liquid 3 stored in a container 2, such as a pail can, using a pump device 4 and supply the suctioned liquid 3 to a predetermined supply destination through a flexible tube 5 and a fixed supply tube 6. As shown in FIGS. 5(a) and 5(b), the pump device 4 includes a casing 7 having a substantially short cylindrical shape. A lower end portion of the casing 7 is formed as a suction port 7a, and an outlet port 7b is formed in the vicinity of an upper end portion of the casing 7. The outlet port 7b is connected to the fixed supply tube 6 via the flexible tube 5. The pump device 4 is attached to a lifting and lowering device 9 via a bracket 8, and can be lifted and lowered by the lifting and lowering device 9.
When pumping out the liquid 3 in the container 2 using the pumping-out apparatus 1, first, as shown in FIG. 5(a), a follow plate 10 is attached to the suction port 7a of the pump device 4. Then, the container 2 storing the liquid 3 is placed under the pump device 4 and mounted on a base 11.
Next, as shown in FIG. 5(b), the lifting and lowering device 9 is activated to lower the pump device 4 and stops lowering the pump device 4 at a position where a lower surface of the follow plate 10 contacts a liquid surface of the liquid 3 in the container 2. Lifting and lowering of the pump device 4 are carried out by causing a chain 9a coupled to the bracket 8 of the pump device 4 to move in a vertical direction.
Next, as shown in FIG. 5(c), the bracket 8 is separated from the chain 9a, so that the pump device 4 can freely move in the vertical direction along a post 12 of the lifting and lowering device 9. After that, the pump device 4 is activated. When the pump device 4 is activated, it can suction the liquid 3 in the container 2 from the suction port 7a, discharge the liquid 3 from the outlet port 7b, and supply the liquid 3 through the flexible tube 5 and the fixed supply tube 6 to the predetermined supply destination. As the liquid 3 in the container 2 decreases by pumping-out the liquid 3 using the pump device 4, the pump device 4 and the follow plate 10 are lowered by their own weights and follow the liquid surface. Therefore, substantially the entire liquid 3 in the container 2 can be pumped out by using the pump device 4.
Moreover, although not shown, another example of the conventional pumping-out apparatuses is that unlike the pumping-out apparatus 1 shown in FIG. 5(c), when pumping out the liquid 3 in the container 2, the pump device 4 is not separated from the chain 9a, and the pump device 4 is lowered by the lifting and lowering device 9 as the liquid surface in the container 2 lowers (see Patent Document 1 for example).    Patent Document 1: Japanese Laid-Open Patent Application Publication 2005-133676